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Endotoxin concentration in contact lens storage cases
G W Fulk1, R D Davis, M M Abbey
1College of Optometry, Northeastern State University, Tahlequah, Oklahoma 74464, USA.
Journal of the American Optometric Association
|May 1, 1997
Summary
Most contact lens cases show gram-negative bacteria contamination, with high endotoxin levels found in some using Opti-Free. This highlights the need for better case hygiene and further investigation into disinfection solution effectiveness.
Area of Science:
- Ophthalmology
- Microbiology
- Public Health
Background:
- Gram-negative bacteria contamination of contact lens storage cases is a known risk factor for ulcerative keratitis.
- Endotoxins, produced by gram-negative bacteria, are key indicators of contamination and potential pathogenicity.
Purpose of the Study:
- To quantify endotoxin concentrations in contact lens storage cases.
- To identify potential correlations between lens care practices and endotoxin levels.
Main Methods:
- The Limulus Amebocyte Lysate (LAL) test was employed to measure endotoxin levels (EU/ml) in 27 contact lens wearers' cases.
- Data on storage solutions, lens wear duration, and lens age were collected for each participant.
Main Results:
- A significant majority (78%) of cases exhibited measurable endotoxin levels.
- Two cases showed exceptionally high endotoxin concentrations (60 EU/ml and 300 EU/ml), both associated with Opti-Free use.
- Five of the top seven highest endotoxin concentrations were linked to Opti-Free users.
Conclusions:
- The LAL test effectively indicated gram-negative bacterial contamination in contact lens cases.
- Widespread endotoxin presence suggests common contamination issues in lens storage.
- Further research is warranted to assess Opti-Free's efficacy in preventing bacterial growth within contact lens cases.